This invention relates to the sealing of vessels at positions where a shaft enters the vessel.
The invention is particularly but not exclusively intended for use in sealing chemical process vessels, such as reaction vessels, where rotatable shafts enter the vessels for the purpose of rotating an agitator or other member within the vessel. In such chemical processing vessels it is obviously necessary so far as possible to prevent any significant escape of the contents of the vessel around the shaft. This is especially difficult when the vessel is maintained at an internal pressure higher than atmospheric pressure. In some cases, such vessels are maintained at pressures which are lower than atmospheric pressure and in that case it is necessary so far as possible to prevent the ingress of any material from outside the vessel. It is usual to employ stuffing boxes as such seals. An object of the present invention is to provide an alternative seal to a stuffing box.